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2
votes
4answers
102 views

Why is dd so slow on raw device, so fast on filesystem (writing on USB key)?

I have a USB key that I am trying to benchmark quick'n'dirty on Linux. dd on raw partition I'm testing write bandwith. I created a partition starting at sector 2048, then did a 4 GB sequential ...
3
votes
3answers
757 views

slow media - disk cache tuning?

Is there any way to make the system more consistent when using LUKS? (or slow storage in general) as it is everything is snappy until the write buffer is full, then everything grinds to a halt as the ...
4
votes
1answer
70 views

Timescales of any task in linux kernel?

I am studying how Linux kernel works and getting interested in the timescale of anything that happens in the kernel. Of course I know it depends on the HW, but would like to get an example. For ...
3
votes
1answer
60 views
+50

RFC 2544 / Y1564 software implementation

Is there any RFC 2544 and/or Y1564 software available for Linux? I'm aware that tools like iperf, bw-ng and bmon exist, but I was not able to find something that mimics Ethernet tester functionality ...
0
votes
1answer
156 views

Performance Issue: AWS Medium Linux Instance V/S Hetzner Dedicated Instance

I am testing an AWS Medium Instance with CentOS (AWS AMI) and comparing it with Hetzner's EX40-SSD (http://www.hetzner.de/hosting/produkte_rootserver/ex40ssd). Software setup on both is comparable( ...
0
votes
1answer
85 views

Is my approach to performance testing in Linux environment correct?

I want to do performance testing in a Linux environment for a C++ application. I need to measure the CPU & Memory usage of the application. This application is a multi-threaded application. In ...
0
votes
1answer
204 views

Samba daemon hammering CPU on CentOS 5.6 VM on bootup

I have a problem where my Centos 5.6 VM is running very slow on my Win7 machine, and looking at top I can see that the Samba daemon smbd is sitting at the top of the list hitting the CPU big time, ...
0
votes
1answer
85 views

udevadm slow boot

After I upgraded from Slackware 13.70 to 14.0, when the machine is booting, it takes it 15 seconds to execute this line: /sbin/udevadm trigger --action=add I understand, that it tries to detect ...
2
votes
0answers
264 views

Local disc copy at 10MB/s! What could be the problem?

I am running a Debian 6.0.6 (before you ask). I have a regular desktop computer, nothing fancy... but when I copy a file using nautilus I am getting 10MB/s copy speed and the system is completely ...
2
votes
0answers
547 views

Send print job to printer immediately without queueing, aka increase print performance

I have a ruby/rails web application, one action of which sends PDF files that have been generated by the app to a Xerox 4127 printer on the network. This is accomplished via shelling out and running ...
2
votes
0answers
389 views

“Remote function call interrupts” (CAL in /proc interrupts). What is it?

I'm running a test program which generates a large number of threads and asynchronous I/O. I'm seeing very high counts of these interrupts in /proc/interrupts, the program cannot scale beyond a ...
2
votes
0answers
193 views

Perform test of aes-ni and aes module in linux kernel

Since both aes-ni and aes module are available in linux kernel , how can I give it a performance test , to decide which one's faster ?
2
votes
0answers
273 views

Software raid checksumming slow

On my new 24 disk array I get 900 MB/s of raw read or write using dd to all the disks. When I set the disks up as a 24 disk RAID6 I get 400 MB/s write and 600 MB/s read. It seems to be due to ...
2
votes
0answers
430 views

GNU/Linux, IO performance problems

I have some problems with my system performance. As I was adviced here, I used sar: $sar -u 5 and found out that the problems are caused by a low HDD performance, as I supposed (high %iowait). ...
2
votes
0answers
942 views

Audio/video out of sync when playing MP4s in mplayer

When I try to play MP4 files in mplayer, after a few seconds I get the "Your system is too SLOW to play this!" warning and the video starts lagging behind the audio. It only happens with MP4s, and ...
1
vote
0answers
13 views

Amount of memory transfer on a running Linux

Can I determinate the amount of RAM exchange (between the CPU and the RAM) on a running Linux system? I'm not looking for the max RAM speed (then memtest would be valid answer). I'm looking for the ...
1
vote
0answers
32 views

memory consumption alert

My VPS has reported a memory consumption alert says reached 273% and I cannot access any of my sites. But I checked on the terminal today and it does not look like a memory problem. Am I correct in ...
1
vote
0answers
71 views

Why does my CMS run extremely slow in my workstation (Ubuntu)

For over a year I have been struggling with the response speed on my Drupal v7.2x CMS install. Let me explain. I'm running Drupal 7.2x on an Ubuntu 12.10 (upgrade to 13.xx pending) for the purpose of ...
1
vote
0answers
203 views

Connected external HDD slows down system

I need to connect large external hard disks (with many many files) to a system running Ubuntu. I have no idea how the Linux kernel is treating the inodes for the external drives, but attaching huge ...
0
votes
0answers
160 views

How can I figure out the reason of the lagging of Cinnamon?

So I am using Mint 15 with Cinnamon on my Dell XPS L502x (Sandy Bridge i7 + 8G + GTX540M + 300G SSD). I am using Numix theme and a custom font. I installed Bumblebee, but I am not using nVidia card in ...
0
votes
0answers
85 views

Troubleshooting Linux performance using KSAR utility

How can I go about troubleshooting Linux performance using the KSAR utility? I already have the data from sar** (sar01, sar02, etc.), but don't have any pointers as to what data relates to what? I am ...
0
votes
0answers
148 views

X high CPU when using Java applications

Only recently, my Freemind program has become extremely sluggish and unresponsive (big lag) when moving my mind map around. I use Arch Linux with xfce4. Freemind is made with Java. If I move the mind ...
0
votes
0answers
315 views

NFS server optimization for maximum performance

I'm looking for maximum of performance for a NFS mount. I'm on local network, it could be completly unsecure, the performance is the most important in my case. What I already found : In /etc/export ...
0
votes
0answers
186 views

write file to NFS speed issue

I have a big data file need to write to NFS directory which is mapped under a Windows system. I had 2 different approaches to achieve this. I wrote (using the “save as” command) from the app directly ...